Can I repair speaker foam?

You can try a little tape on the back side, but I would bring it in to a shop and have them put a new surround on.

I can second Millersound.

Go on eBay under Polk and buy the refoaming kit. I did it myself so I am sure you can do it as well. It just takes some time and effort. Good luck.

i take it that you dont want to replace the damaged speaker or send it off for a refoam job,you can buy a product called (vulkem)that will repair the tear,vulkem is a polyurathene sealent that comes in a standard sized caulking tube & it can be bought at most professional glass shops that sell high performance sealents,if your local glass shop dont have vulkem then ask for (sikaflex 1a) which is also a butyl based sealent that dries flexible.

both products should cost less than a $5 spot & they both come in colors that will half ass match your surround.

Refoaming a speaker is easy.
Just make certain the cone is centered and it is a snap.
Total klutzs need to have someone else do it.